Digital Addressable Lighting Interface (DALI) is a network-based system which may control lighting in building automation and is a standard communication protocol intended to control light sources. The hierarchical network is comprised of two basic types of devices: single DALI Master and multiple DALI Slaves, where the format of the data transferred over the network differs between DALI Master and DALI Slaves. DALI Slave is synonymous for a light-producing system in connection with a DALI bus. These light producing systems are sometimes called Electronic Control Gears (ECGs). Besides ECGs, there may be other devices on the DALI network, for example sensors. A DALI Master, or Master lighting device, is a special controller, which when connected to the DALI network, provides power for the operation of DALI slaves and implements the DALI communication protocol. The main feature of the protocol is that a DALI Master initiates all communication, such as sending queries and setting parameters, to which DALI Slaves, in some cases, may respond or, in other cases, need not respond.
In one case, two separate devices, Master and Slave were used on the network. However, this case introduced the problem of how to implement the devices such that both Master and Slave communicated with a single micro-controller, considering the isolation requirement of both Master and Slave. Implementation of both in a single microcontroller increases the complexity of how the two interfaces are managed, as the Slave needs to run continuously, e.g. to check whether there is a Master on the Slave's network, while the Master may be turned on depending on internal logic.
In a known example of DALI functionality, an interface bridge is placed between a standard input-output (I/O) computer port and a DALI interface. The bridge uses a standard Digital communication interface to receive and send data to a supervising device.
In another known example, a controller may automatically recognize a light control network, and utilizes what is called “bus controller” in mixed mode operation. The DALI network is detected by the controller and sends commands as DALI Master through such network, thereby combining DALI Master and Slave functions.